Conventionally, a waterproof structure for an end part of a multicore sheathed cable is known from Japanese Unexamined Patent Publication No. 2003-174716 (patent literature 1). This waterproof structure is such that a tubular body is mounted on the tip of a sheath of the multicore sheathed cable from which a plurality of wires are pulled out, and a sealing material such as silicon-based adhesive is filled into the interior of this tubular body.
In the above multicore sheathed cable, the tip of a nozzle is first inserted into a clearance between the sheath and the tubular body and, after a sealing agent is injected from the tip of the nozzle, the tip of the nozzle is inserted between a plurality of wires and the sealing material is injected between each of the plurality of wires. In this way, sealing is provided between the wires and the sheath and between each of the plurality of wires.